From e7fab38387df0f99f8bdee20c79c9c1517fd5fb9 Mon Sep 17 00:00:00 2001
From: Bobby Holley <bobbyholley@gmail.com>
Date: Thu, 5 May 2016 16:33:45 -0700
Subject: [PATCH] Bug 1270515 - Avoid synthesizing temporary nsStyleCoords in
 nsStyleSides::ConvertsToLength. r=dbaron

---
 layout/style/nsStyleCoord.h  | 18 ++++++++++++++----
 layout/style/nsStyleStruct.h |  4 ----
 2 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/layout/style/nsStyleCoord.h b/layout/style/nsStyleCoord.h
index 986b3aa95bca..70a13e948842 100644
--- a/layout/style/nsStyleCoord.h
+++ b/layout/style/nsStyleCoord.h
@@ -174,9 +174,14 @@ public:
            (IsCalcUnit() && CalcHasPercent());
   }
 
+  static bool ConvertsToLength(const nsStyleUnit aUnit,
+                               const nsStyleUnion aValue) {
+    return aUnit == eStyleUnit_Coord ||
+           (IsCalcUnit(aUnit) && !AsCalcValue(aValue)->mHasPercent);
+  }
+
   bool ConvertsToLength() const {
-    return mUnit == eStyleUnit_Coord ||
-           (IsCalcUnit() && !CalcHasPercent());
+    return ConvertsToLength(mUnit, mValue);
   }
 
   nscoord ToLength() const {
@@ -188,6 +193,11 @@ public:
     return GetCalcValue()->ToLength();
   }
 
+  // Callers must verify IsCalcUnit before calling this function.
+  static Calc* AsCalcValue(nsStyleUnion aValue) {
+    return static_cast<Calc*>(aValue.mPointer);
+  }
+
   nscoord     GetCoordValue() const;
   int32_t     GetIntValue() const;
   float       GetPercentValue() const;
@@ -292,7 +302,7 @@ public:
 
   bool ConvertsToLength() const {
     NS_FOR_CSS_SIDES(side) {
-      if (!Get(side).ConvertsToLength()) {
+      if (!nsStyleCoord::ConvertsToLength(mUnits[side], mValues[side])) {
         return false;
       }
     }
@@ -435,7 +445,7 @@ inline nsStyleCoord::Calc* nsStyleCoord::GetCalcValue() const
 {
   NS_ASSERTION(IsCalcUnit(), "not a pointer value");
   if (IsCalcUnit()) {
-    return static_cast<Calc*>(mValue.mPointer);
+    return AsCalcValue(mValue);
   }
   return nullptr;
 }
diff --git a/layout/style/nsStyleStruct.h b/layout/style/nsStyleStruct.h
index bb6b526e8636..8be0a332c26a 100644
--- a/layout/style/nsStyleStruct.h
+++ b/layout/style/nsStyleStruct.h
@@ -824,10 +824,6 @@ struct MOZ_NEEDS_MEMMOVABLE_MEMBERS nsStyleMargin
 
   nsStyleSides  mMargin;          // [reset] coord, percent, calc, auto
 
-  bool IsWidthDependent() const {
-    return !mMargin.ConvertsToLength();
-  }
-
   bool GetMargin(nsMargin& aMargin) const
   {
     if (mMargin.ConvertsToLength()) {